Long-term operation of planar InGaAs/InP p-i-n photodiodes

The long-term stability of planar InGaAs p-i-n photodiodes with InP cap layer and SiN_x passivation at elevated temperatures up to 200°C is discussed. An increase of the dark current with saturation at the level of a few nanoamperes has been observed as the only chip-related degradation mode. In additional experiments this increase has been identified as surface leakage current flowing due to charge transfer in the SiN_x and to changes in the InP-SiN_x interface state density. For a dark current increase to 1 nA under 15-V reverse-bias voltage at room temperature, a median lifetime of 10⁹ h has been extrapolated